I would (and do) err on the side of caution, you need to think about durable medical equipment, MRIs and other items that only get coverage with B.
My most recent MRI was $7500, 20% of that came to $1500. My mammo last week cost me $7.51 vs. $300 & change. Pap smears & annual physical, routine blood work, IVSM (the cost of the help, not the juice) walkers, scooters, manual wheel chairs and all that stuff get 80% coverage. One hit like that could destroy a year's budget.
Never forget that unless you're admitted, visits to the ER don't count as hospitalization. Ask around among your adults and find out how many people have had freak/stupid injuries, without MS.
Take serious care against assuming that the only thing that could go wrong would be MS related or within your normal routine. No one plans to trip in a doorway, over a pet, or step in a sinkhole in their lawn.
It's a huge gamble with not-so-good odds.
On the other hand, that +/- $100 a month could buy a lot of candy and magazines.